Fermium (Fm) is a synthetic element with the atomic number 100, placing it within the actinide series of the periodic table. It is a highly radioactive metal that does not occur naturally on Earth. Fermium has no commercial or industrial applications, and its sole purpose lies in advancing the field of nuclear science within specialized research facilities.
Understanding Fermium’s Creation and Rarity
Fermium is generated through a complex chain of nuclear reactions within high-flux nuclear reactors. This process involves the intense bombardment of lighter actinide elements, such as plutonium or curium, with neutrons. The starting material captures multiple neutrons, undergoing successive beta decays to transmute into fermium isotopes.
The primary source for producing these heavy, synthetic elements is the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory in the United States. Even with this specialized equipment, only microscopic quantities are successfully isolated. Fermium-257, the most stable isotope, is typically produced in picogram amounts (a millionth of a millionth of a gram).
This challenging production method and vanishingly small yield translate directly to its scarcity. Fermium is the heaviest element that can be created through neutron capture, marking the end of this production path. The logistical difficulty of working with such minute, highly radioactive samples is a fundamental hurdle in its study.
Role in Nuclear Chemistry Research
The research use of Fermium centers on its unique position in the periodic table, acting as a bridge to heavier elements. Scientists use Fermium isotopes as target material in particle accelerators to synthesize trans-fermium elements, such as Nobelium (element 102) and Lawrencium (element 103). High-energy beams are directed at the target to fuse nuclei, creating these new, heavier atoms.
Studying Fermium helps researchers investigate the limits of nuclear stability and the behavior of matter at the extreme end of the periodic table. Experiments focus on how the element’s nucleus handles a high number of protons and neutrons, which validates or challenges current nuclear models. For instance, the spontaneous fission properties of Fermium isotopes provide data on the shell structure of heavy nuclei.
Chemists also study Fermium’s chemical properties, although they must do so using tracer amounts in solution. This research helps understand the trends in the actinide series, particularly how the element’s valence electrons behave compared to lighter elements. Understanding these properties provides insight into the architecture of the periodic table beyond the naturally occurring elements.
Properties That Preclude Practical Uses
The intense radioactivity and short life span of Fermium isotopes make any practical application impossible. Fermium-257, the most long-lived isotope, possesses a half-life of only about 100.5 days, meaning half of any collected sample decays quickly. Most other isotopes have half-lives measured in hours, minutes, or even milliseconds, preventing their long-term accumulation or storage.
A further limitation is the “fermium gap,” which occurs during production inside a nuclear reactor. As Fermium-257 is produced, it rapidly absorbs a neutron to become Fermium-258. This new isotope instantly undergoes spontaneous fission, destroying itself immediately. This inherent instability prevents Fermium from being reliably extracted in quantities large enough for any purpose outside of immediate, highly specialized research.